diff mbox

[7/7] Kbuild: lto: pass -m32/-m64 to to LDFINAL

Message ID nycvar.YSQ.7.76.1802021523390.1842@knanqh.ubzr (mailing list archive)
State New, archived
Headers show

Commit Message

Nicolas Pitre Feb. 2, 2018, 8:38 p.m. UTC 
On Fri, 2 Feb 2018, Arnd Bergmann wrote:

> Do you have a git tree with other changes for LTO on ARM? I'd
> like to try that as well.

I currently have only 2 other patches.

You need commit 75fea300d73a that just hit mainline (you may cherry-pick 
it easily if necessary).

Then the following:

----- >8
Subject: [PATCH] HACK: enable LTO on ARM

Without the ${KBUILD_VMLINUX_LIBS} move the build fails with missing
memcpy all over the place. Didn't figure it out yet.







> 
>        Arnd
> 
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Comments

Arnd Bergmann Feb. 2, 2018, 8:55 p.m. UTC | #1 
On Fri, Feb 2, 2018 at 9:38 PM, Nicolas Pitre <nicolas.pitre@linaro.org> wrote:
> On Fri, 2 Feb 2018, Arnd Bergmann wrote:
>
>> Do you have a git tree with other changes for LTO on ARM? I'd
>> like to try that as well.
>
> I currently have only 2 other patches.
>
> You need commit 75fea300d73a that just hit mainline (you may cherry-pick
> it easily if necessary).

Ok, I apparently have that already by basing on today's linux-next.

> Then the following:
>
> ----- >8
> Subject: [PATCH] HACK: enable LTO on ARM
>
> Without the ${KBUILD_VMLINUX_LIBS} move the build fails with missing
> memcpy all over the place. Didn't figure it out yet.

Added that now as well, thanks! I'll see what comes out of it. Have you
tried arm64 already? I suppose I could do the same change there and
see what happens.

      Arnd
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Nicolas Pitre Feb. 2, 2018, 9:17 p.m. UTC | #2 
On Fri, 2 Feb 2018, Arnd Bergmann wrote:

> On Fri, Feb 2, 2018 at 9:38 PM, Nicolas Pitre <nicolas.pitre@linaro.org> wrote:
> > On Fri, 2 Feb 2018, Arnd Bergmann wrote:
> >
> >> Do you have a git tree with other changes for LTO on ARM? I'd
> >> like to try that as well.
> >
> > I currently have only 2 other patches.
> >
> > You need commit 75fea300d73a that just hit mainline (you may cherry-pick
> > it easily if necessary).
> 
> Ok, I apparently have that already by basing on today's linux-next.

OK. linux-next has had it for quite a while.

> > Then the following:
> >
> > ----- >8
> > Subject: [PATCH] HACK: enable LTO on ARM
> >
> > Without the ${KBUILD_VMLINUX_LIBS} move the build fails with missing
> > memcpy all over the place. Didn't figure it out yet.
> 
> Added that now as well, thanks! I'll see what comes out of it.

I forgot: you'll need to hack your toolchain a bit too.

Here's the script I created to remember about the issue:

----- >8
#!/bin/bash

# work around https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78353

GCC_ROOT=/opt/gcc-linaro-6.3.1-2017.05-x86_64_arm-linux-gnueabihf

set -e
set -x

cd $GCC_ROOT//arm-linux-gnueabihf/bin
[ -e fat-as ] && exit 1
mv as fat-as
cat > as << EOF
#!/bin/bash
exec -a "\$0" "\$(dirname "\$0")/fat-as" -mimplicit-it=always "\$@"
EOF
chmod +x as
8< -----

> Have you tried arm64 already? I suppose I could do the same change 
> there and see what happens.

No, didn't try arm64.


Nicolas
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diff mbox

Patch

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 4382315005..84450843ed 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -17,6 +17,7 @@  config ARM
 	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
 	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
 	select ARCH_SUPPORTS_ATOMIC_RMW
+	select ARCH_SUPPORTS_LTO
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF
 	select ARCH_WANT_IPC_PARSE_VERSION
@@ -101,6 +102,7 @@  config ARM
 	select PERF_USE_VMALLOC
 	select RTC_LIB
 	select SYS_SUPPORTS_APM_EMULATION
+	select THIN_ARCHIVES if LTO
 	# Above selects are sorted alphabetically; please add new ones
 	# according to that.  Thanks.
 	help
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 45a6b9b7af..39ac0a9639 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -97,7 +97,7 @@  targets       := vmlinux vmlinux.lds piggy_data piggy.o \
 clean-files += piggy_data lib1funcs.S ashldi3.S bswapsdi2.S \
 		$(libfdt) $(libfdt_hdrs) hyp-stub.S
 
-KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
+KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING $(DISABLE_LTO)
 
 ifeq ($(CONFIG_FUNCTION_TRACER),y)
 ORIG_CFLAGS := $(KBUILD_CFLAGS)
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 964b2ee855..0774a87788 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -99,9 +99,9 @@  vmlinux_link()
 		if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
 			objects="--whole-archive			\
 				built-in.o				\
+				${KBUILD_VMLINUX_LIBS}			\
 				--no-whole-archive			\
 				--start-group				\
-				${KBUILD_VMLINUX_LIBS}			\
 				--end-group				\
 				${1}"
 		else